BARRINGTON, Ill. (STMW) — Two students at a northwest suburban middle school have been suspended after the district investigated a series of alleged sexual abuse incidents that took place earlier this month on a school bus, Pioneer Press is reporting.

Tom Leonard, superintendent of Barrington School District 220, sent a letter to parents Tuesday notifying the community of the reported assaults, which officials said occurred over a four-day period from Oct. 1 to Oct. 4.

“The bus driver noticed some questionable activity going on in the back of the bus,” said Jeff Arnett, chief communications officer for District 220. “Almost at the same time, a student submitted a bullying report on behalf of the student on the bus.”

The report, Arnett said, prompted Prairie Middle School officials to examine surveillance videos taken on the bus.

“Upon closer inspection of videos, they found sufficient evidence to involve the police,” he said.

The superintendent’s letter states that Barrington police referred both students to the Cook County State’s Attorney’s office on Oct. 5.

Leonard said the alleged incidents and investigation were not made public earlier because of the complex and delicate nature of the situation.

“The investigation determined that no more than three students were directly involved in this incident,” the letter to parents stated. “Because some may question the severity of the punishment-to-date for the two young male students, I can only tell you that their consequences are fair and appropriate given the circumstances.”

The two male students have been suspended until further notice, Arnett said.

The student victim is receiving counseling, he said, and part of the reason the incidents were not reported sooner was to give that student sufficient time and opportunity to acclimate back into the school day.

Counselors have been made available to all Prairie students.

Leonard urged parents to encourage their children to immediately share anything they see out of the ordinary or any uncomfortable situation they may encounter.